1. Field of the Invention
The present invention relates to an interactive video system and more particularly to a system and method for creating and playback of interactive video. In a development mode of operation, the system automatically tracks a pixel object in a video sequence that has been selected in a video frame and generates one or more linked video files representative of the location of the selected object in all of the frames in the sequence, along with links to data objects for use in conjunction with an interactive video system. In a playback mode of operation, the system enables the pixel objects to be selected during subsequent playback of the video frames with a pointing device, such as a mouse, providing access to linked data objects.
2. Description of the Prior Art
There is a trend toward interactive video for various commercial, educational and entertainment purposes. To provide such interactivity, video content producers need to link various desired video or pixel objects within each of the video frames of the video content with data objects, such as web pages. In order to provide links for selected pixel objects in the various video frames, video content producers are known to implement image processing techniques for linking selected pixel objects in each of the various video frames to other platforms. Both manual and automatic image processing techniques are known.
Examples of systems in which the links are manually “authored” are disclosed in U.S. Pat. Nos. 5,774,666; 6,076,104 and 5,929,849. In general, manual image processing techniques involve editing each video frame in a video sequence and manually embedding links or hot spots in each of the frames for the desired pixel objects. Such a task is extremely labor intensive and thus expensive to implement. For example, a 30-minute television show is known to include 22 minutes of video content and 8 minutes of advertising inserts. At a playback rate of 30 frames per second, the 22 minutes of video content is comprised of (30 frames/second×60 seconds/minute×22 minutes) 39,600 frames. In order to provide the ability for interactivity, a video content producer thus would need to edit 39,600 frames for a 22-minute broadcast and embed links in each of the frames for one or more various objects. As mentioned above, such a task is extremely labor intensive and thus relatively expensive.
In order to improve image processing of video content for the purpose of providing interactivity by providing links to various objects within the video frames, automatic image processing systems have been developed that are able to automatically track an object in a video frame sequence and link the pixel objects to other platforms. Examples of such automatic authoring systems are disclosed in U.S. Pat. Nos. 6,205,231; 6,169,573 and 5,867,584.
U.S. Pat. No. 6,169,573 relates to a system for tracking objects in a sequence of video frames which track objects in a compressed format using variables encoded in MPEG compressed video content. Unfortunately, the system disclosed in the '573 patent is only useful for tracking objects in MPEG format and is not suitable for use with video content in an uncompressed format or other video format, such as .mov.
U.S. Pat. No. 6,205,231 discloses an image processing system that is able to automatically track an object in a video frame sequence. The system disclosed in the '231 patent incorporates known image processing techniques for tracking an edge of an object based on its color or luminosity characteristics. The system disclosed in the '231 patent “tags” selected objects in the video frame sequence which enables the tags and thus the selected object to be linked to other platforms, such as websites.
There are various problems with the system such as disclosed in the '231 patent, such as inaccurate tracking of the pixel object. In particular, image processing systems, such as disclosed in the '231 patent locate pixel objects within a video frame by locating pixels having a certain color variable value. Unfortunately, the color variable values for an object may change from scene to scene due to lighting effects or due to the effects of the decompression. The system disclosed in the '231 patent does not compensate for such changes and thus is not able to accurately track pixel objects in a video frame sequence. In addition, embedding tags in the original video content is resource intensive requiring relatively high level computing platforms.
U.S. Pat. No. 5,867,584 also relates to an image processing system for automatically tracking objects in a video frame sequence. This system attempts to anticipate the position of the selected object in succeeding frames by generating a number of virtual wire frames along a predetermined anticipatory trajectory of the pixel object in succeeding frames and comparing the pixel variables within the test windows of the anticipatory trajectory with the original test window. As such, the system disclosed in the '584 patent is resource intensive. In addition, the system utilizes known image processing techniques based on the intensity characteristic of the pixels within the windows. As such, the system disclosed in the '584 patent does not take into account changes in brightness and shifts in the hue due to lighting effects in the video frame and thus is unable to accurately track an object in a sequence of video frames. Thus, there is a need for image processing system for automatically tracking a selected object in a video frame sequence that is able to relatively accurately track the object and is not resource intensive.